Killer stoat drags native chicks out of burrows
A conservation group is reeling after a stoat decimated a population of closely-monitored native chicks that were about to fledge.
Twenty-four-hour cameras captured the predator dragging oi, or grey-faced petrel, chicks out of burrows on Karioi Maunga at Raglan.
Those trying to protect the birds discovered what had happened in the last week of November.
‘‘I’ll never forget putting my hand down those burrows,’’ said Karioi Maunga ki te Moana manager Kristel van Houte, who was hoping to band the chicks for future tracking.
‘‘It was empty, empty, empty. ‘‘You’re kind of waiting for the peck . . . My heart just went, oh, no’’.
The conservation group was devastated as staffers and volunteers had spent about six months trying to protect the chicks.
They were in a colony near Indicators, down the coast from Whale Bay, and were weeks off being ready to leave the nest.
Karioi Maunga ki te Moana started in 2009, and one aim of the multi-agency project is to reestablish Karioi as a seabird mountain.
It got a $429,000 boost from Waikato Regional Council in
2016.
The oi chicks which bred in
2017 were the first known ones for at least a decade, van Houte said.
‘‘A couple of weeks ago, we thought we might get about 14 or
15 chicks away [this year] and then we had this incursion, and it’s probably halved our numbers,’’ she said.
‘‘It was devastating, actually.’’ Cameras used to monitor burrows showed that, over several days, the stoat killed the chicks and dragged them out.
The Indicators burrows were found on private property in 2017.
The group is working with landowners to get full protection in place, but had hoped to get the chicks through with what they had.
Oi can fly to Japan or South America in a couple of days, van Houte said, and they’re also good divers and agile on land.
More are breeding at Karioi maunga now that there’s more predator control in place.
Oi parents share care of the eggs and chicks, she said, but return to sea for long periods to search for food.
‘‘Basically, from July, when that chick hatches, to December when it flies off, it sits in the burrow by itself, and it’s incredibly vulnerable.’’
The Karioi Maunga ki te Moana project tries to protect the chicks, using monitoring, 24-hour cameras, and predator control.
Since the death of the chicks, the group has trapped two stoats nearby, and hopes that will protect the other oi sites.
Killing one animal to save another is a challenge for many conservationists, van Houte said.
But ‘‘one stoat incursion can nail a whole seabird population’’.
The Department of Conservation describes stoats as ‘‘public enemy number one’’ for New Zealand birds.
According to New Zealand Birds Online, oi are not classed as threatened, though they’re said to be making a comeback as breeding islands are cleared of pests.
‘‘I’ll never forget putting my hand down those burrows.’’ Karioi Maunga ki te Moana manager Kristel van Houte